Synthesis of InP quantum dot decorated Bi2WO6 microspheres for the efficient photocatalytic production of hydrogen peroxide in water

Abstract

Most photocatalysts reported to date need sacrificial agents (ethanol or methanol) to quench h⁺ and facilitate the reduction of O₂ to H₂O₂. This requirement increases the cost of H₂O₂ production and hinders the advancement of photocatalytic technology. Exploring a novel photocatalyst without the sacrificial agents for photocatalytic production of H₂O₂ remains a huge challenge. In this research, we designed Indium phosphide (InP) quantum dot (QDs)-decorated bismuth tungstate (Bi₂WO₆) microspheres for the photocatalytic generation of H₂O₂ without the use of any sacrificial agents. The photocatalytic efficiency of InP/Bi₂WO₆ composites for H₂O₂ production reached 17.45 mmol g⁻¹ h⁻¹, which is 90.8 times and 53.6 times greater than pure InP and Bi₂WO₆, respectively. Furthermore, InP/Bi₂WO₆ composites demonstrated high photocatalytic H₂O₂ production efficiency when used in industrial wastewater and tap water. In addition, in-situ photocatalytic H₂O₂ synthesis was applied to actual coking wastewater for lowering chemical oxygen demand (COD) levels, and the removal rate was more than 60%. Remarkably, the degradation efficiency of acid orange 7 using the 3InP/Bi₂WO₆ sample reached 99.9%. To the best of our knowledge, no other research has reported the use of InP QDs for the photocatalytic in-situ synthesis of H₂O₂ in real water. This study provides valuable insights for the development of InP-based photocatalysts.